This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. The subproject and investigator (PI) may have received primary funding from another NIH source, and thus could be represented in other CRISP entries. The institution listed is for the Center, which is not necessarily the institution for the investigator. I am trying to pinpoint the cell of origin/location of origin of primitive hindrain tumors in mice. I am using a Nestin-inducible transgenic strain to post-natally mutate neurogenic stem cells in mice, and with a mutant Smoothened gene I can fairly predictably generate primitive tumors in the hindbrain that resemble medulloblastomas. I have been trying to capture very early tumors by sacrificing animals before they develop neurogenic symptoms, but the tumors seem to grow so rapidly that I either find no tumor or advanced tumor. It is proving very unwieldy to perfuse, sacrifice, section, and stain so many animals in this way, so I want to use MRI (7T) to monitor living mice for the development of early tumors, and to watch their progression and spread. Live imaging will be a far more effective means of tracking early tumor development, pinpointing the site of origin, and determining whether this site of origin is always the same. Future plans are to use these mice as preclinical models to test drugs: MRI tracking of drug response will be critical.